The compound, N-(4-((3-(2-amino-4-pyrimidinyl)-2-pyridinyl)oxy)phenyl)-4-(4-methyl-2-thienyl)-1-phthalazinamine, also chemically named as 4-((3-(2-amino-pyrimidin-4-yl)-pyridin-2-yl)oxy)phenyl-(4-(4-methyl-thiophen-2-yl)-phthalazin-1-yl)amine, and is referred to herein as “AMG 900” has a chemical structure of

AMG 900 is an ATP competitive small molecule Aurora kinase inhibitor that is highly potent and selective for Aurora kinases A, B and C. AMG 900 is disclosed in US patent publication no. 20070185111, which published on Aug. 9, 2007 and issued as U.S. Pat. No. 7,560,551. AMG 900 is further disclosed in US patent publication no. 20090163501, now U.S. Pat. No. 8,022,221. Various uses and applications of AMG 900 are described in patent publications US20120028917 and WO2013149026. AMG 900 is being clinically evaluated primarily for its safety, tolerability and pharmacokinetic (PK) profile in human phase I trials for (1) advanced solid tumors (US Clinical Trial Id No. NCT00858377), and (2) for acute leukemias (US Clinical Trial Id No. NCT1380756).
Different solid state forms of a given compound are typically investigated to determine whether or not a particular form possesses and/or exhibits desirable properties allowing that compound to be clinically and/or commercially developed. Such beneficial and advantageous properties, by way of example, include without limitation, crystallinity, improved thermodynamic stability, non-hygroscopicity, high purity, minimal to total absence of moisture and/or residual solvents, chemical stability, high yielding synthetic process and/or manufacturability and reproducibility, desirable biopharmaceutical properties including improved dissolution characteristics and increased bioavailability, absence or reduced toxicities due to reduced or limited exposure, rate of exposure or release, or related to counter ions, good bulk and formulation properties including good flow, bulk density, desirable particle size and the like, or a combination of the aforementioned characteristic attributes.
Generally when a compound, also referred to herein as drug substance (DS), has been identified as a developmental candidate, the DS is screened to identify potentially beneficial polymorphic, crystalline or solid state forms of the compound and/or a pharmaceutically acceptable salt thereof. X-ray diffraction, Raman, solid state NMR and a melting point temperature and/or a melting point temperature range have been typically used to monitor or screen and identify the different polymorphic form of the DS. Different polymorphic forms of a given DS can have an impact on that compound's solubility, stability and bioavailability. Also, it is important to monitor possible changes in polymorphic forms of the DS during stability studies.
AMG 900 was previously isolated and identified as a free base compound. This compound exhibited rather lack-luster pharmacokinetic (PK) and/or pharmacodynamic (PD) properties, including poor aqueous solubility, poor bioavailability, poor absorption, poor target exposure and overall, a not-so-attractive in-vivo efficacy profile. Thus, there is a need to address and solve the technical problem of identifying alternative forms of AMG 900 to achieve substantially the same effect or an improved effect, including improved PK and PD profiles, as that of AMG 900 known in the art.